Article
Multidisciplinary Sciences
Hamza K. Khattak, Stefan Karpitschka, Jacco H. Snoeijer, Kari Dalnoki-Veress
Summary: The dynamic changes of elastic deformation of soft substrates at a microscale and the decrease of force when the film thickness decreases were studied and explained. The relationship between dissipation intensity and film thickness was discovered.
NATURE COMMUNICATIONS
(2022)
Article
Chemistry, Physical
Stephan Handschuh-Wang, Ben Wang, Tao Wang, Florian J. Stadler
Summary: Liquid and fusible metals have attracted significant attention due to their unique thermophysical properties, such as thermal and electrical conductivity and low phase transition temperature. They are widely used in welding, soldering, and thermal transport. Accurate measurement of surface tension and its temperature coefficient is crucial for these applications. Various measurement methods have been developed, and this review discusses the main principles, reasons for preference, and challenges associated with surface tension measurements of liquid metals.
SURFACES AND INTERFACES
(2023)
Article
Multidisciplinary Sciences
Nevin Brosius, Kevin Ward, Evan Wilson, Zachary Karpinsky, Michael SanSoucie, Takehiko Ishikawa, Satoshi Matsumoto, Ranga Narayanan
Summary: The Faraday forcing method was introduced as a new way to measure surface tension in levitated liquid droplets, offering advantages for high viscosity samples. This study presents an experimental method to measure surface tension by exciting different oscillation modes and provides a more rigorous quantification of droplet excitation. Surface tension measurements using this method compare favorably to literature values for various materials, establishing it as a credible benchmarking technique.
Article
Mechanics
Alexander Nepomnyashchy, Ilya Simanovskii
Summary: This study investigates the effect of vibration on Marangoni flows in a droplet on a liquid substrate. Numerical analysis using longwave amplitude equations shows that vibration can change the shape of the droplet, resulting in rhombic droplets. The shape of the droplet significantly influences its oscillations.
Article
Chemistry, Multidisciplinary
Veronika Turinicova, Martin Mosko, Pavol Durina, Syed A. M. Tofail, Tomas Roch, Maros Gregor
Summary: A simple noninvasive measurement method is developed to determine the trapped charge in a biocompatible hydroxyapatite dielectric. The trapped charge is determined by analyzing the shape change of a liquid droplet hanging from a needle near the charged sample surface. The method is easily implementable into standard pendant drop setups, and it demonstrates a long-term charge stability of the charged hydroxyapatite.
Article
Physics, Applied
Sizhu Wu, Le Xiang, Yiyuan Zhang, Shaojun Jiang, Chuanzong Li, Zhipeng Zhao, Yiyuan Zhang, Qiyu Deng, Shuting Xie, Yunlong Jiao, Chao Chen, Zhaoxin Lao, Liqiu Wang
Summary: This study reports an active and directional steering of omni-droplets using bi-directional vibration on slippery cross-scale structures. The steering relies on the competition between vertical and horizontal forces originating from circular arc arrays and slant ratchet arrays, respectively. Various steering modes, including climbing and programmable manipulation, can be achieved.
APPLIED PHYSICS LETTERS
(2023)
Article
Chemistry, Physical
C. W. Extrand
Summary: This study discusses the surface tension of very small liquid drops and proposes a simple analytical model to predict the changes at the nanoscopic scale. The study finds that the surface tension decreases exponentially for drops with diameters less than a few nanometers and/or containing less than several thousand atoms or molecules. These findings align with earlier simulation and experimental studies.
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
(2023)
Article
Physics, Fluids & Plasmas
Vincent Bertin, Jacco H. Snoeijer, Elie Raphael, Thomas Salez
Summary: The passage discusses the process of a solid entraining a liquid film when withdrawn from a wetting liquid bath, which has applications in everyday life and industry. A new dip-coating model accounting for a soft solid layer is developed, leading to the discovery of a new softness-dependent power-law regime in the entrained liquid thickness.
PHYSICAL REVIEW FLUIDS
(2022)
Article
Chemistry, Multidisciplinary
C. W. Extrand
Summary: This theoretical work estimates the volume and energies associated with the formation of a liquid meniscus along a vertical flat wall using existing equations. A proposed mechanism and energy balance is presented, along with derived equations for wetting work, surface energy, gravitational energy, and dissipation. The analysis indicates that the energy released during wetting is stored in various forms depending on variables such as surface tension, density, and wall wettability.
Article
Physics, Multidisciplinary
Adam Fortais, Kathleen Charlesworth, Rafael D. Schulman, Kari Dalnoki-Veress
Summary: The study reveals that the elastocapillary interaction between flexible microfibers and bubbles trapped at the surface of a liquid bath can cause the microfibers to wrap into a coil around the perimeter of the bubble, leading to an increased bubble lifetime. A simple model incorporating surface and bending energies captures the spontaneous winding process observed in the study.
PHYSICAL REVIEW LETTERS
(2021)
Article
Engineering, Chemical
Yingchun Wu, Qimeng Lv, Xuecheng Wu, Xinhao Wang, Linghong Chen, Kefa Cen
Summary: The oscillation of micron-sized liquid droplets can be measured using time-resolved rainbow refractometry to determine surface tension and viscosity. The method shows potential for improving experimental validation and reducing measurement errors, with relative errors of less than 5% for surface tension and 10% for viscosity.
Article
Physics, Multidisciplinary
Melody X. Lim, Bryan VanSaders, Anton Souslov, Heinrich M. Jaeger
Summary: We investigate a model system for the rotational dynamics of inertial many-particle clustering, where submillimeter objects are acoustically levitated in air. Driven by scattered sound, these levitated grains selfassemble into a monolayer of particles, forming mesoscopic granular rafts. Detuning the acoustic trap imparts angular momentum to the levitated objects, causing the rafts to deform and eventually break into separate rafts, resembling the breakup of a liquid drop.
Article
Chemistry, Multidisciplinary
Francesco Ricci, Marc T. Cuairan, Andreas W. Schell, Erik Hebestreit, Raul A. Rica, Nadine Meyer, Romain Quidant
Summary: A single levitated nanoparticle is used as a nanoreactor to study surface chemistry at the nanoscale. The optical levitation technique provides precise control over the nanoparticle's dynamics, charge, and surface chemistry. By studying a single nanoparticle, the researchers were able to observe how the presence of silanol groups on its surface affects water adsorption and desorption from the surrounding gas. They demonstrated the potential of this versatile platform by studying the Zhuravlev model in silica particles, and observed an abrupt and irreversible change in scattering cross section, mass, and mechanical eigenfrequency during the dehydroxylation process.
Article
Mechanics
M. Rubio, P. Rodriguez-Diaz, J. M. Lopez-Herrera, M. A. Herrada, A. M. Ganan-Calvo, J. M. Montanero
Summary: We experimentally and numerically investigate the onset of tip streaming in an electrified droplet. Our experiments reveal that when the droplet has a sufficiently small dimensionless conductivity, it oscillates at the apex before ejecting a liquid jet. This oscillatory behavior is due to limited charge transfer from the bulk to the interface, reducing the electrostatic pressure at the droplet's stretching tip. The reduction in electrostatic pressure is compensated by electric shear stress during oscillations, leading to jet formation. The stability limit calculated from global stability analysis agrees well with experimental results, but predicts non-oscillatory, non-localized instability, suggesting that tip streaming arises during nonlinear droplet deformation.
Article
Chemistry, Physical
Alexandra Dobosz, Rada Novakovic, Tomasz Gancarz
Summary: Liquid metals have become increasingly important as functional materials in recent years. This work investigated the thermophysical properties of liquid Ga-Sn-Zn alloys with different compositions, showing discrepancies between experimental data and model predictions. Various models were used to analyze viscosity, density, and surface tension of the alloys.
JOURNAL OF MOLECULAR LIQUIDS
(2021)
Article
Mechanics
Dipin S. Pillai, R. Narayanan
FLUID DYNAMICS RESEARCH
(2018)
Article
Mechanics
Dipin S. Pillai, R. Narayanan
JOURNAL OF FLUID MECHANICS
(2018)
Article
Physics, Fluids & Plasmas
S. Diwakar, Vibhor Jajoo, Sakir Amiroudine, Satoshi Matsumoto, Ranga Narayanan, Farzam Zoueshtiagh
PHYSICAL REVIEW FLUIDS
(2018)
Article
Mechanics
Dipin S. Pillai, R. Narayanan
JOURNAL OF FLUID MECHANICS
(2018)
Article
Mechanics
Kevin Ward, Satoshi Matsumoto, Ranga Narayanan
JOURNAL OF FLUID MECHANICS
(2019)
Article
Mechanics
Georg F. Dietze, Jason R. Picardo, R. Narayanan
JOURNAL OF FLUID MECHANICS
(2018)
Article
Mechanics
Dipin S. Pillai, R. Narayanan
JOURNAL OF FLUID MECHANICS
(2018)
Article
Engineering, Mechanical
Kevin Ward, Farzam Zoueshtiagh, Ranga Narayanan
EXPERIMENTS IN FLUIDS
(2019)
Article
Physics, Fluids & Plasmas
Kevin Ward, Farzam Zoueshtiagh, Ranga Narayanan
PHYSICAL REVIEW FLUIDS
(2019)
Article
Physics, Fluids & Plasmas
P. Lin, X. Lin, L. E. Johns, R. Narayanan
PHYSICAL REVIEW FLUIDS
(2019)
Article
Physics, Fluids & Plasmas
Dipin S. Pillai, Kirti Chandra Sahu, Ranga Narayanan
Summary: This study investigates the wetting and contact line dynamics of a leaky dielectric sessile droplet under an alternating electrostatic field applied in the vertical direction. The droplet oscillates with a frequency twice that of the forcing potential due to the quadratic dependence of the Maxwell stress on the applied ac electric field, and the contact line motion increases monotonically with the amplitude of the ac electric forcing. A significant increase in ac field may lead to spiking and interface ruptures at the top electrode.
PHYSICAL REVIEW FLUIDS
(2021)
Editorial Material
Multidisciplinary Sciences
Ranga Narayanan, Brian Motil
Article
Multidisciplinary Sciences
Nevin Brosius, Jason Livesay, Zachary Karpinski, Robert Singiser, Michael SanSoucie, Brandon Phillips, Ranga Narayanan
Summary: The dynamics of levitated liquid droplets can be used to measure their thermophysical properties. In this study, it was shown that the resonance of the first and fourth principal modes of oscillation can be accurately measured using electrostatic levitation. The shadow array method may also be used to obtain consistent benchmark of thermophysical properties.
Review
Multidisciplinary Sciences
B. Dinesh, J. Livesay, I. B. Ignatius, R. Narayanan
Summary: This article reviews two types of resonance-derived interfacial instability, with a focus on the effect of side walls on interfacial mode discretization. The first type is mechanical Faraday instability, and the second is electrostatic Faraday instability. Both resonances are discussed for single-frequency forcing. In the case of mechanical resonance, inviscid theory can predict the expected modal forms when viscosity is considered, and experiments validate the theory. The article also examines electrostatic resonant instability, which leads to a specific mode resembling Rayleigh Taylor instability, and experiments show good agreement with theoretical predictions. An important distinction between the two resonances is the gradual rise in negative detuning instability observed in mechanical Faraday's case, compared to the sharp rise in the case of electrostatic resonance.
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2023)